Stay on 4.4!
I tested 4.6 many hours out and there are many problems with 4.6 and no 4.4.

Example of problems in version 4.6:

- T/D-Point is gone and the "trick" of 4.4 is no longer working.
- Fuel consumption of the 757-200 models are wrong.
- If you Load your fuel after the aircraft is loaded, you can not use the autpilot-knob for SPD/IAS longer.
- Vnav descent calculation is poor.